What antibiotic is recommended for a urinary tract infection (UTI) caused by Pseudomonas?

Antibiotic Treatment for Pseudomonas UTI

For urinary tract infections caused by Pseudomonas aeruginosa, levofloxacin 750 mg once daily for 10 days is the recommended fluoroquinolone regimen, though combination therapy with an anti-pseudomonal β-lactam (such as ceftazidime, cefepime, or piperacillin-tazobactam) should be strongly considered for severe infections or when resistance is suspected. 1

First-Line Treatment Approach

Fluoroquinolone Monotherapy (Mild-Moderate Cases)

• Levofloxacin 750 mg orally once daily for 10 days is FDA-approved specifically for complicated UTIs caused by Pseudomonas aeruginosa 1
• Ciprofloxacin 500-750 mg twice daily represents an alternative fluoroquinolone option with established efficacy against Pseudomonas 2, 3
• The higher dose of ciprofloxacin (750 mg twice daily) should be used when treating less susceptible Pseudomonas strains 2

Combination Therapy (Severe Cases or High Resistance Risk)

• When Pseudomonas is documented or presumed, combination therapy with an anti-pseudomonal β-lactam is recommended 1
• Anti-pseudomonal β-lactams include: ceftazidime 2g IV every 8 hours, cefepime 2g IV every 8-12 hours, or piperacillin-tazobactam 3.375-4.5g IV every 6 hours 4
• This combination approach is particularly critical in nosocomial infections or when local resistance patterns are concerning 1

Alternative Regimens for Resistant Pseudomonas

For Difficult-to-Treat Pseudomonas (DTR-PA)

• Ceftolozane-tazobactam 1.5-3g IV every 8 hours is a preferred option for multidrug-resistant strains 4
• Ceftazidime-avibactam 2.5g IV every 8 hours provides coverage for resistant Pseudomonas 4, 5
• Imipenem-cilastatin-relebactam 1.25g IV every 6 hours offers carbapenem-based coverage 4

For Carbapenem-Resistant Pseudomonas (CRPA)

• Colistin-based therapy (5 mg CBA/kg IV loading dose, then 2.5 mg CBA × [1.5 × CrCl + 30] IV every 12 hours) can be used as monotherapy or combination therapy 4
• Cefiderocol represents a newer option for highly resistant strains 5
• Aminoglycosides (amikacin 15 mg/kg IV once daily) may be considered, though only as monotherapy for uncomplicated UTIs 4

Critical Treatment Considerations

Catheter Management

• If an indwelling catheter has been in place ≥2 weeks, replace it before initiating antibiotics to improve outcomes and reduce recurrence 4, 6
• Obtain urine culture from the freshly placed catheter prior to starting treatment 4, 6
• Treatment duration remains 7-14 days regardless of whether the catheter stays in place 4, 6

Culture-Guided Therapy

• Always obtain urine culture before starting antibiotics due to the wide spectrum of potential organisms and high likelihood of resistance 4, 6
• Susceptibility testing is essential as Pseudomonas resistance patterns vary significantly by institution and geographic region 4, 5
• Monitor for resistance development during therapy, particularly when initial MIC values are elevated 7

Treatment Duration

• 10-14 days is the standard duration for Pseudomonas UTI 4
• Shorter courses (5-7 days) are inadequate for Pseudomonas infections, even with prompt symptom resolution 4
• Extended therapy may be necessary for delayed clinical response or complicated anatomical factors 4, 6

Key Pitfalls to Avoid

• Do not use moxifloxacin for UTIs due to inadequate urinary concentrations 6
• Avoid fluoroquinolone monotherapy in patients with recent fluoroquinolone exposure or known ESBL-producing organisms 5
• Do not use aminoglycosides as monotherapy except for uncomplicated UTIs, as they require combination therapy for complicated infections 4
• Resistance can develop rapidly during therapy, particularly when treating Pseudomonas with borderline susceptibility (MIC >0.5 mg/L) 7
• Consider local antibiogram data as resistance patterns may be significantly higher in healthcare-exposed patients 6